
This is what we are after, for it's nice looking skin.
And here is where we find it:

I suggest you start from the Marketplace to get to The Undercity.
What are we up against: Kappa
What skills do they use? Conjure Frost, Rust, Mind Freeze, Enervating Charge
And Baubao? Same skill setup as the rest, only he is level 24.
Weapon Set:
Stance or while Hexed equipment, funnily enough the very item your farming is perfect for the build it self.
Mods: Prefix: Barbed, Cruel, Furious.
Suffix: Warding, Defense, Fortitude.
Skills:
Sever, Gash, Victory is Mine, Sprint, Elemental Resistance, Watch Yourself, Healing Signet, Dolyak Signet.
Attribute Points:
7-8 inspiration
5 Strenght
12-14 Sword
Maxed out Tactics.
The attributes are not set in stone, neither are the skills. Depending on either Legionnaire's or Beserkers you can experiment with superior / minor runes to your liking. The numbers provided are mearly an indication of what you could use. A Lieutenants Helm could be used.
Getting to the Undercity is not much of a problem, just heal up in a safe spot using Healing Signet. Might take you a few tries to figure out the fastest way to get there, but it's not hard so I'll leave you to it.
Once in the Undercity follow the map provided, sprinting past any Am Fah you encounter. Once you reach a merchant and a weapon crafter(who provides equipemnt 'while hexed'). There are 2 / 3 groups of Kappa. Aggro all of them between Sever / Gash / ViM you be able to survive with the tanking skills provided. Spread the conditions among several of em and use ViM accordingly. When not under Rust (won't happen often), you are free to use Healing Signet.
Drops?
About 2-3k in drops. The Shell itself randomly haven't been able to put a number on it yet.
Difficulty: Only tricky part might be the run at times, even that is easy enough. The Kappa are nothing to worry about.
Enjoy this little farm,
Courage